- DL manuals
- Yamaha
- Outboard Motor
- 25B
- Owner's Manual
Yamaha 25B Owner's Manual
Summary of 25B
Page 1
Q q q q read this manual carefully before operating this outboard motor. Owner’s manual e25b 25b 25x 30h 69r-28199-28-e0
Page 2
Emu25052 read this manual carefully before operating this outboard motor. Keep this manual onboard in a waterproof bag when boating. This manual should stay with the outboard motor if it is sold..
Page 3: Important Manual Information
Important manual information emu25105 to the owner thank you for choosing a yamaha outboard motor. This owner’s manual contains infor- mation needed for proper operation, mainte- nance and care. A thorough understanding of these simple instructions will help you ob- tain maximum enjoyment from your ...
Page 4: Table of Contents
Table of contents safety information............................. 1 outboard motor safety .................... 1 propeller............................................ 1 rotating parts.................................... 1 hot parts ........................................... 1 electric shock ..........
Page 5: Table of Contents
Table of contents installation ..................................... 25 mounting the outboard motor .......... 25 clamping the outboard motor ......... 26 operation ......................................... 28 first-time operation ....................... 28 breaking in engine ..........................
Page 6: Safety Information
1 safety information emu33622 outboard motor safety observe these precautions at all times. Emu36500 propeller people can be injured or killed if they come in contact with the propeller. The propeller can keep moving even when the motor is in neutral, and sharp edges of the propeller can cut even wh...
Page 7: Safety Information
Safety information 2 death when inhaled. Symptoms include nau- sea, dizziness, and drowsiness. Keep cock- pit and cabin areas well ventilated. Avoid blocking exhaust outlets. Emu33780 modifications do not attempt to modify this outboard mo- tor. Modifications to your outboard motor may reduce safety...
Page 8: Safety Information
Safety information 3 operate defensively at safe speeds and keep a safe distance away from people, ob- jects, and other boats. ● do not follow directly behind other boats or waterskiers. ● avoid sharp turns or other maneuvers that make it hard for others to avoid you or un- derstand where you are go...
Page 9: General Information
4 general information emu25171 identification numbers record emu25183 outboard motor serial number the outboard motor serial number is stamped on the label attached to the port side of the clamp bracket. Record your outboard motor serial number in the spaces provided to assist you in ordering spare ...
Page 10: General Information
General information 5 emu25213 c-tick label engines affixed with this label conform to certain portion(s) of the australian radio communications act. 1. Ce marking location 1. C-tick label location 1 zmu04730 zmu06040 1 zmu05721 zmu01697.
Page 11: General Information
General information 6 emu33520 read manuals and labels before operating or working on this motor: ● read this manual. ● read any manuals supplied with the boat. ● read all labels on the outboard motor and the boat. If you need any additional information, contact your yamaha dealer. Emu33831 warning ...
Page 12: General Information
General information 7 emu33912 contents of labels the above warning labels mean as follows. 1 warning ewm01691 emergency starting does not have start- in-gear protection. Ensure shift control is in neutral before starting engine. 2 warning ewm01681 ● keep hands, hair, and clothing away from rotating...
Page 13: General Information
General information 8 emu33843 symbols the following symbols mean as follows. Notice/warning read owner’s manual hazard caused by continuous rotation electrical hazard remote control lever/gear shift lever operat- ing direction, dual direction engine start/ engine cranking zmu05696 zmu05664 zmu05665...
Page 14: Specifications
9 specifications and requirements emu31480 specifications tip: “(al)” stated in the specification data below represents the numerical value for the alumi- num propeller installed. Likewise, “(sus)” represents the value for stainless steel propeller installed and “(pl)” for plastic propeller installe...
Page 15: Installation Requirements
Specifications and requirements 10 spark plug gap: 0.9–1.0 mm (0.035–0.039 in) control system: 25bmh tiller 25xmh tiller 30hmh tiller 30hw remote control e25bmh tiller starting system: 25bmh manual 25xmh manual 30hmh manual 30hw manual and electric e25bmh manual starting carburetion system: choke va...
Page 16: Remote Control Requirements
Specifications and requirements 11 tor(s) does not exceed the boats maximum horsepower rating. See the boat’s capacity plate or contact the manufacturer. Emu33571 mounting motor warning ewm01570 ● improper mounting of the outboard mo- tor could result in hazardous condi- tions such as poor handling,...
Page 17: Propeller Selection
Specifications and requirements 12 accessories rated to withstand 18 volts or higher with the above models. Consult your yamaha dealer for details on installing an optional rectifier regulator. Emu34191 propeller selection next to selecting an outboard, choosing the right propeller is one of the mos...
Page 18: Engine Oil Requirements
Specifications and requirements 13 emu25651 engine oil requirements if the recommended engine oil is not avail- able, another 2-stroke engine oil with an nmma-certified tc-w3 rating may be used. Emu36360 fuel requirements emu36770 gasoline use a good quality gasoline that meets the minimum octane ra...
Page 19: Emergency Equipment
Specifications and requirements 14 emu36351 emergency equipment keep the following items onboard in case there is trouble with the motor. ● a tool kit with assorted screwdrivers, pli- ers, wrenches (including metric sizes), and electrical tape. ● waterproof flashlight with extra batteries. ● an extr...
Page 20: Components
15 components emu2579h components diagram tip: * may not be exactly as shown; also may not be included as standard equipment on all mod- els. E25b, 25b, 25x, 30h emu25802 fuel tank if your model was equipped with a portable fuel tank, its function is as follows. Warning ewm00020 the fuel tank suppli...
Page 21: Components
Components 16 be used as a fuel storage container. Com- mercial users should conform to relevant licensing or approval authority regula- tions. Emu25830 fuel joint this joint is used to connect the fuel line. Emu25841 fuel gauge this gauge is located on either the fuel tank cap or on the fuel joint ...
Page 22: Components
Components 17 emu26201 neutral interlock trigger to shift out of neutral, first pull the neutral in- terlock trigger up. Emu26211 neutral throttle lever to open the throttle without shifting into ei- ther forward or reverse, put the remote con- trol lever in the neutral position and lift the neutral...
Page 23: Components
Components 18 emu25941 throttle grip the throttle grip is on the tiller handle. Turn the grip counterclockwise to increase speed and clockwise to decrease speed. Emu25961 throttle indicator the fuel consumption curve on the throttle indicator shows the relative amount of fuel consumed for each throt...
Page 24: Components
Components 19 when constant speed is desired, tighten the adjuster to maintain the desired throttle set- ting. Emu25993 engine shut-off cord (lanyard) and clip the clip must be attached to the engine shut- off switch for the engine to run. The cord should be attached to a secure place on the operato...
Page 25: Components
Components 20 emu26011 choke knob for pull type to supply the engine with the rich fuel mix- ture required to start, pull out this knob. Emu26070 manual starter handle to start the engine, first gently pull the han- dle out until resistance is felt. From that posi- tion, then pull the handle straigh...
Page 26: Components
Components 21 to increase resistance, turn the adjuster clockwise. To decrease resistance, turn the adjuster counterclockwise. Warning ewm00040 do not overtighten the friction adjuster. If there is too much resistance, it could be difficult to steer, which could result in an accident. Emu26253 trim ...
Page 27: Components
Components 22 emu30530 tilt lock mechanism the tilt lock mechanism is used to prevent the outboard motor from lifting out of the wa- ter when in reverse gear. To lock it, set the tilt lock lever in the lock po- sition. To release, push the tilt lock lever in the release position. Emu26321 tilt suppo...
Page 28: Components
Components 23 emu26410 2-pin connector ac 12 v-40/60/80w power is delivered through this connector. When using it, keep in mind the following points: ● use a genuine yamaha connector. ● use lighting equipment only. ● connect lighting equipment directly to the 2-pin connector. ● capacity of the light...
Page 29: Engine Control System
24 engine control system emu26803 alert system notice ecm00091 do not continue to operate the engine if a alert device has activated. Consult your yamaha dealer if the problem cannot be located and corrected. Emu2681a overheat alert this engine has an overheat-alert device. If the engine temperature...
Page 30: Installation
25 installation emu26902 installation the information presented in this section is intended as reference only. It is not possible to provide complete instructions for every possible boat and motor combination. Prop- er mounting depends in part on experience and the specific boat and motor combinatio...
Page 31: Installation
Installation 26 notice ecm01630 ● during water testing, check the buoy- ancy of the boat, at rest, with its maxi- mum load. Check that the static water level on the exhaust housing is low enough to prevent water entry into the power head when water rises due to waves when the outboard is not run- ni...
Page 32: Installation
Installation 27 3. Secure the clamp bracket to the transom using the bolts provided with the out- board (if packed). For details, consult your yamaha dealer. Warning! Avoid using bolts, nuts or washers other than those contained in the engine packaging. If used, they must be of at least the same qua...
Page 33: Operation
28 operation emu36380 first-time operation emu30174 breaking in engine your new engine requires a period of break- in to allow mating surfaces of moving parts to wear in evenly. Correct break-in will help en- sure proper performance and longer engine life. Notice: failure to follow the break-in proc...
Page 34: Operation
Operation 29 emu37141 fuel level be sure you have plenty of fuel for your trip. A good rule is to use 1/3 of your fuel to get to the destination, 1/3 to return, and to keep 1/ 3 as an emergency reserve. With the boat level on a trailer or in the water, check the fuel level. For fuel filling instruct...
Page 35: Operation
Operation 30 unrestricted throughout the whole range with no binding or excessive free play. ● operate the throttle levers several times to make sure there is no hesitation in their travel. Operation should be smooth over the complete range of motion, and each le- ver should return completely to the...
Page 36: Operation
Operation 31 emu36581 battery check that the battery is in good condition, and fully charged. Check that the battery connections are clean, secure and covered by insulating covers. The electrical contacts of the battery and cables must be clean and properly connected or the battery will not start th...
Page 37: Operation
Operation 32 ture. ● if the mixture is not thoroughly mixed, or if the mixing ratio is incorrect, the following problems could occur. ● low oil ratio: lack of oil could cause major engine trouble, such as piston seizure. ● high oil ratio: too much oil could cause fouled spark plugs, smoky exhaust, a...
Page 38: Operation
Operation 33 the oil gradually as the gasoline is being add- ed to the tank. Emu27451 operating engine emu27464 feeding fuel (portable tank) warning ewm00420 ● before starting the engine, make sure that the boat is tightly moored and that you can steer clear of any obstructions. Be sure there are no...
Page 39: Operation
Operation 34 emu27492 starting engine warning ewm01600 before starting the engine, make sure that the boat is tightly moored and that you can steer clear of any obstructions. Be sure there are no swimmers in the wa- ter near you. Emu27508 manual start models (tiller control) warning ewm01840 ● failu...
Page 40: Operation
Operation 35 tip: ● it is not necessary to use the choke when starting a warm engine. ● if the choke knob is left in the “ ” (start) position while the engine is running, the engine will run poorly or stall. 5. Pull the manual starter handle slowly un- til you feel resistance. Then give a strong pul...
Page 41: Operation
Operation 36 be thrown forward. 1. Place the remote control lever in neutral. Tip: the start-in-gear protection device prevents the engine from starting except when in neu- tral. 2. Attach the engine shut-off cord to a se- cure place on your clothing, or your arm or leg. Then install the clip on the...
Page 42: Operation
Operation 37 6. After the engine starts, slowly return the manual starter handle to its original po- sition before releasing it. Tip: ● when the engine is cold, it needs to be warmed up. For further information, see page 39. ● if the engine does not start on the first try, repeat the procedure. If t...
Page 43: Operation
Operation 38 4. Open the throttle slightly without shifting using the neutral throttle lever or free ac- celerator. You may need to change the throttle opening slightly depending on engine temperature. After the engine starts, return the throttle to the original position. Tip: ● on remote controls e...
Page 44: Operation
Operation 39 of cranking, return the main switch to “ ” (on), wait 10 seconds, then crank the engine again. [ecm00192] emu36510 checks after starting engine emu36520 cooling water check for a steady flow of water from the cooling water pilot hole. A continuous flow of water from the pilot hole shows...
Page 45: Operation
Operation 40 engine and allow it to warm up. To shift out of neutral 1. Pull the neutral interlock trigger up (if equipped). 2. Move the remote control lever / gear shift lever firmly and crisply forward (for forward gear) or backward (for reverse gear) [about 35° (a detent can felt) for re- mote co...
Page 46: Operation
Operation 41 2. After the engine is at idle speed in gear move the remote control lever / gear shift lever firmly and crisply into the neu- tral position. Emu31742 stopping boat warning ewm01510 ● do not use the reverse function to slow down or stop the boat as it could cause you to lose control, be...
Page 47: Operation
Operation 42 2. After stopping the engine, disconnect the fuel line if there is a fuel joint on the outboard motor. 3. Tighten the air vent screw on the fuel tank cap (if equipped). 4. Remove the key if the boat will be left unattended. Tip: the engine can also be stopped by pulling the cord and rem...
Page 48: Operation
Operation 43 emu27872 adjusting trim angle for manual tilt models there are 4 or 5 holes provided in the clamp bracket to adjust the outboard motor trim an- gle. 1. Stop the engine. 2. Tilt the outboard motor up, and then re- move the trim rod from the clamp brack- et. 3. Reposition the rod in the d...
Page 49: Operation
Operation 44 bow up, the boat may have a greater tenden- cy to steer to one side or the other. Compen- sate for this as you steer. The trim tab can also be adjusted to help offset this effect. When the bow of the boat is down, it is easier to accelerate from a standing start onto plane. Bow up too m...
Page 50: Operation
Operation 45 few minutes. Otherwise fuel may leak. Notice ecm00241 ● before tilting the outboard motor, stop the engine by following the procedure on page 41. Never tilt the outboard mo- tor while the engine is running. Severe damage from overheating can result. ● do not tilt up the engine by pushin...
Page 51: Operation
Operation 46 emu28013 procedure for tilting down (manual tilt models) 1. Slightly tilt the engine up. 2. On models equipped with a tilt support knob, pull it out. 3. Slowly tilt the engine down. Emu28061 shallow water emu28073 cruising in shallow water (manual tilt models) warning ewm01781 ● run the...
Page 52: Operation
Operation 47 2. Push the tilt lock lever down to the re- lease position. 3. Slightly tilt the outboard motor up and pull the shallow water lever toward the transom. 4. To return the outboard motor to the nor- mal position, place the remote control le- ver / gear shift lever in neutral, then slightly...
Page 53: Maintenance
48 maintenance emu28225 transporting and storing outboard motor warning ewm00692 ● use care when transporting fuel tank, whether in a boat or car. ● do not fill fuel container to maximum capacity. Gasoline will expand consid- erably as it warms up and can build up pressure in the fuel container. Thi...
Page 54: Maintenance
Maintenance 49 lowing procedures. Notice ecm01411 ● do not place the outboard motor on its side before the cooling water has drained from it completely, otherwise water may enter the cylinder through the exhaust port and cause engine trou- ble. ● store the outboard motor in a dry, well- ventilated p...
Page 55: Maintenance
Maintenance 50 stops. 11. Drain the cooling water completely out of the motor. Clean the body thoroughly. 12. If the “fogging oil” is not available, re- move the spark plug(s). Pour a tea- spoonful of clean engine oil into each cylinder. Crank several times manually. Replace the spark plug(s). 13. D...
Page 56: Maintenance
Maintenance 51 tor before operation. Emu28511 replacement parts if replacement parts are necessary, use only genuine yamaha parts or parts of equivalent design and quality. Any part of inferior quality may malfunction, and the resulting loss of control could endanger the operator and passengers. Yam...
Page 57: Maintenance
Maintenance 52 emu34445 maintenance chart 1 tip: ● refer to the sections in this chapter for explanations of each owner-specific action. ● the maintenance cycle on these charts assume usage of 100 hours per year and regular flushing of the cooling water passages. Maintenance frequency should be adju...
Page 58: Maintenance
Maintenance 53 fuel line(high pres- sure) inspection or replace- ment as necessary fuel line(low pres- sure) inspection fuel line(low pres- sure) inspection or replace- ment as necessary fuel pump inspection or replace- ment as necessary fuel/oil leakage inspection gear oil replacement greasing poin...
Page 59: Maintenance
Maintenance 54 emu34451 maintenance chart 2 item actions every 1000 hours guide exhaust/exhaust manifold inspection or replace- ment as necessary.
Page 60: Maintenance
Maintenance 55 emu28941 greasing yamaha grease a (water resistant grease) yamaha grease d (corrosion resistant grease; for propeller shaft) e25b, 25b, 25x, 30h emu28954 cleaning and adjusting spark plug the spark plug is an important engine com- ponent and is easy to inspect. The condition of the sp...
Page 61: Maintenance
Maintenance 56 move and inspect the spark plug because heat and deposits will cause the spark plug to slowly break down and erode. If electrode erosion becomes excessive, or if carbon and other deposits are excessive, you should re- place the spark plug with another of the cor- rect type. 1. Remove ...
Page 62: Maintenance
Maintenance 57 emu29041 inspecting idling speed warning ewm00451 ● do not touch or remove electrical parts when starting or during operation. ● keep hands, hair, and clothes away from the flywheel and other rotating parts while the engine is running. Notice ecm00490 this procedure must be performed ...
Page 63: Maintenance
Maintenance 58 checkpoints ● check each of the propeller blades for wear, erosion from cavitation or ventila- tion, or other damage. ● check the propeller shaft for damage. ● check the splines for wear or damage. ● check for fish line tangled around the pro- peller shaft. ● check the propeller shaft...
Page 64: Maintenance
Maintenance 59 specified torque. 4. Align the propeller nut with the propeller shaft hole. Insert a new cotter pin in the hole and bend the cotter pin ends. Notice: do not reuse the cotter pin installed. Otherwise the propeller can come off during operation. [ecm01890] tip: if the propeller nut does...
Page 65: Maintenance
Maintenance 60 ing device, inject the gear oil into the gear oil drain screw hole. 6. Put a new gasket on the oil level plug. When the oil begins to flow out of the oil level plug hole, insert and tighten the oil level plug. 7. Put a new gasket on the gear oil drain screw. Insert and tighten the gea...
Page 66: Maintenance
Maintenance 61 4. Clean the filter (located on the end of the suction pipe) in a suitable cleaning sol- vent. Allow the filter to dry. 5. Replace the gasket with a new one. Re- install the fuel joint assembly and tighten the screws firmly. Emu29312 inspecting and replacing anode(s) yamaha outboard m...
Page 67: Maintenance
Maintenance 62 2. Check the battery’s charge. If your boat is equipped with the digital speedome- ter, the voltmeter and low battery alert functions will help you monitor the bat- tery’s charge. If the battery needs charg- ing, consult your yamaha dealer. 3. Check the battery connections. They shoul...
Page 68: Trouble Recovery
63 trouble recovery emu29427 troubleshooting a problem in the fuel, compression, or igni- tion systems can cause poor starting, loss of power, or other problems. This section de- scribes basic checks and possible remedies, and covers all yamaha outboard motors. Therefore some items may not apply to ...
Page 69: Trouble Recovery
Trouble recovery 64 q. Is fuel system obstructed? A. Check for pinched or kinked fuel line or other obstructions in fuel system. Q. Is fuel contaminated or stale? A. Fill tank with clean, fresh fuel. Q. Is fuel filter clogged? A. Clean or replace filter. Q. Have ignition parts failed? A. Have servic...
Page 70: Trouble Recovery
Trouble recovery 65 q. Is load on boat improperly distributed? A. Distribute load to place boat on an even plane. Q. Is water pump or thermostat faulty? A. Have serviced by a yamaha dealer. Q. Is there excess water in fuel filter cup? A. Drain filter cup. Engine power loss. Q. Is propeller damaged? ...
Page 71: Trouble Recovery
Trouble recovery 66 q. Is fuel joint connection incorrect? A. Connect correctly. Q. Is heat range of spark plug incorrect? A. Inspect spark plug and replace it with rec- ommended type. Q. Is high pressure fuel pump drive belt bro- ken? A. Have serviced by a yamaha dealer. Q. Is engine not responding...
Page 72: Trouble Recovery
Trouble recovery 67 consult your yamaha dealer if the new fuse immediately blows again. Emu29533 starter will not operate if the starter mechanism does not operate (the engine cannot be cranked with the start- er), the engine can be started with an emer- gency starter rope. Warning ewm01022 ● use th...
Page 73: Trouble Recovery
Trouble recovery 68 3. Remove the starter/flywheel cover after removing the bolt(s). 4. Prepare the engine for starting. For fur- ther information, see page 34. Be sure the engine is in neutral and that the clip is attached to the engine shut-off switch. The main switch must be “ ” (on), if equipped...
Page 74
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